The effect of intermittent hypoxic exposure on running and swimming performance was evaluated. Athletes (swimmers = 13; runners = 10) were matched and assigned to either a hypobaric hypoxic or normobaric normoxic group. Hypoxia was simulated for an altitude of 4,000 to 5,000 meters. Both groups rested for three hours per day, five days per week, for four weeks in a hypobaric chamber, but under the differing conditions of altitude simulation. Performance was measured before and after the treatment with runners covering 3,000 m and swimmers 100 and 400 m in time trials.

No significant changes in time trial performances for either runners or swimmers, between or within groups.